In general, at the time of taking out a liquid chemical from a vial, a metallic injection needle is made to directly puncture a rubber stopper (stopper) of the vial and the liquid chemical is sucked out. However, troubles such as accidental sticking with the injection needle or leakage of the liquid chemical via a gap between the injection needle and the rubber stopper may occur. Especially, when the liquid chemical is a dangerous drug such as a carcinostatic agent, leakage of the liquid chemical poses a risk of damaging the health of the person who prepares the drug. In view of this, in recent years, vial adapters permitting easy drug preparation without leakage of the drug to the exterior have been proposed. Examples of general vial adapters in the conventional technique have included a vial adapter, which includes a fitting portion having a plurality of claws for fitting a vial therein, a metallic or resin made (plastic-made) needle provided with a liquid chemical passage, and a connector for connection to a syringe, in which a fitting portion having claws and a needle are integrally molded by injection molding or the like (see, for example, Japanese Laid-Open Patent Publication No. 2005-516696 (PCT), Japanese Laid-Open Patent Publication No. 2005-504609 (PCT), and Japanese Laid-Open Patent Publication No. 2005-522282 (PCT)).